SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
This thread is privately moderated by hoppy, who may elect to delete unwanted replies.
Old Jul 03, 2009, 12:48 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
Discussion
Lipo Storage Voltage and Dead Battery Information

About once a week (or oftener) someone posts a question on how, or whether to, revive an over discharged Lipo battery or What is the best storage voltage.
Here are some of the recent threads on that subject. I'm sure you will find an answer to your question in one of them.

Best Storage Voltage is 40-50% charged or about 3.78-3.85V/cell.
The recommended minimum charge temperature according to several sources is 32F.
Probably at no more than a 1C charge rate.
http://www.ibt-power.com/bkencel/Lithium-Po-tech.html
http://ultralifecorporation.com/download/168/
http://powerelectronics.com/site-fil...ttery-life.pdf
http://www.powerstream.com/li.htm

(Remember, overdischarged lipos are damaged goods and the safety precautions recommended for lipo packs should be followed. Using damaged packs is not recommended)
Over-discharging can cause internal damage to electrodes and current collectors
(i.e., dissolution of copper) , can lead to lithium plating if the cell is recharged
(particularly, if the cell is repeatedly over-discharged), and can ultimately lead to thermal runaway"


Consider this before doing any recovery attempts.

(HOW TO) Recovering over discharged lipos
http://www.rcgroups.com/forums/showthread.php?t=1072324

dead lipo how to charge it
http://www.rcgroups.com/forums/showthread.php?t=1002464

Can I save this lipo?
http://www.rcgroups.com/forums/showthread.php?t=1072215

How to charge or discharge single cells to balance a pack.
http://www.rcgroups.com/forums/showp...89&postcount=2
hoppy is offline Find More Posts by hoppy
Last edited by hoppy; Oct 26, 2014 at 11:39 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 07, 2009, 01:21 PM
Registered User
Dan Baldwin's Avatar
United States, CA, Norwalk
Joined Apr 2004
2,724 Posts
There will alway be people who will start a new thread even if the answer to their question is on the first page of this forum, but I think the stickys have helped A LOT. The "Complete Guide to Lithium Polymer Batteries and LiPo Failure Reports" has almost 1/3 million views. That's an average of about 147 views PER DAY. You have to think that many of those people found the answer to their questions, and as a result, did not start another thread.

I think that this thread would be a valuable sticky, and one specifically aimed at "What's the best charger" would be good too.

Dan
Dan Baldwin is online now Find More Posts by Dan Baldwin
Reply With Quote
Old Aug 22, 2010, 12:12 PM
Registered User
NL
Joined Nov 2009
304 Posts
Those other threads recommend charging around 0.3C until the battery is above "too low" threshold for the LIPO charger. I found a manual for a LIPO cell once (but I've since lost it), and it recommended charging "really slow". I think it mentioned 0.1C, but can't be sure. Anyway
- Charge really slowly as long as they are below 3.0V. (0.1C recommended)
- Damage is done by TIME below 3.0V. So recharge with this procedure ASAP when you notice you've left your battery on.
rewolff is offline Find More Posts by rewolff
Reply With Quote
Old Oct 22, 2010, 12:24 AM
Registered User
USA, TN, Dickson
Joined Dec 2003
220 Posts
What a Great Thread!

Just a couple of months back and plus being new to any type of elec. flying except for a GWS Tiger Moth that was all stock with no upgrades I had went on the battery section of the forums and ask if there was anyway at all I could save my Brand New Lipo that I had left plugged in to the plane by mistake and it drained the battery to the point to where it showed zero voltage. The answer I got was to cut the plugs off and disgard the new pack (3 cell) and that''s just what I did. Being my very first Lipo and brushless set-up that really hurt!! If I had read this post in time just maybe I could have saved the pack? It was just a 20.00 pack but just being a week old and now was told it was junk kinda hurt a little. I sure hated cutting those plugs off that new pack but that's what I was told to do and that's what I did. Thanks for this info and maybe next time it happens (Which I don't think it will) as now atleast I know and very careful about leaving one pluged up!! Now if I'm very careful just maybe I can save a pack or atleast have a chance...

Again, Thanks for the info and instrutions on how to do this! VERY good informantion that I will not forget and you can take that to the BANK!!

Best Regards,
Ben Morrow
Ben Morrow is offline Find More Posts by Ben Morrow
Reply With Quote
Old Oct 22, 2010, 09:09 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
Ben,
Tossing a pack that had been under load for 1 week and was at 0V was not a bad thing to do.
Once the cells go below 2.5V the battery starts to undergo permanent damage which can not be undone.
Here's a reference on what happens inside the pack once the voltage/temp goes outside the safe operating window. http://www.mpoweruk.com/lithium_failures.htm
Running the pack below 2.5V/cell causes the copper anode to dissolve.

The best hope for "saving" cells is when the pack has gone just a little under the range where the charger won't turn on and it hasn't been at that low level for very long.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Oct 22, 2010, 04:04 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
I don't remmember recommending any units from 2dodrc but that's neither here nor there.
I suggest you post this question as a new thread in the forum, you'll probably get more responses.
Cell checkers will work with any manufacturers pack - the only "but" is that the connectors must match up.
For instance, Polyquest uses a 5 pin connector for 3s packs using pins 1,3,4,5 as I recall whereas Hobbyking and many others use a 4 pin connector in a 1,2,3,4 combo for 3 cells. TP uses a smaller 4 pin connector using pins 1,2,3,4. If all your packs match the pin wiring on your tester, no problem. Otherwise you'll need adapters to match them up.
hoppy is offline Find More Posts by hoppy
Last edited by hoppy; Oct 22, 2010 at 04:10 PM.
Reply With Quote
Old Nov 11, 2010, 04:02 AM
Registered User
lipoflyer's Avatar
Australia
Joined Nov 2010
2,876 Posts
Quote:
Originally Posted by rewolff View Post
Those other threads recommend charging around 0.3C until the battery is above "too low" threshold for the LIPO charger. I found a manual for a LIPO cell once (but I've since lost it), and it recommended charging "really slow". I think it mentioned 0.1C, but can't be sure. Anyway
- Charge really slowly as long as they are below 3.0V. (0.1C recommended)
- Damage is done by TIME below 3.0V. So recharge with this procedure ASAP when you notice you've left your battery on.
I've revived a few turnigy and Rhino packs by charging them at 100ma.

I sat the batteries in a lipo safe during the charge. i once upon a time tried to revive a lipo by charging it at 2c.......there was a fire.

100ma worked for me
lipoflyer is offline Find More Posts by lipoflyer
Reply With Quote
Old Nov 14, 2010, 10:18 AM
Registered User
Joined Jul 2009
56 Posts
This is great battery info... i think there is almost impossible to charge a dead lipo, should try the info, tks
rcairplanes is offline Find More Posts by rcairplanes
Reply With Quote
Old Nov 16, 2010, 04:41 PM
Registered User
Raehm's Avatar
Charleston, SC
Joined Jul 2006
852 Posts
re: re-soldering battery leads

Can anyone advise me on the correct and safe procedure for re-soldering a charger lead to a cell?

Thanks,
Raehm is offline Find More Posts by Raehm
Reply With Quote
Old Nov 16, 2010, 09:38 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
Picture?
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Dec 26, 2010, 02:11 PM
Registered User
USA, PA, Harleysville
Joined Aug 2010
107 Posts
thanks for putting this info together in one place. very helppful

my situation is a little different than the links you posted.

I have that parkzone ulta micro 4 battery charger. I had 4 charging at the time i bought my wildcat. then i left them sit in the charger for a month or two :|

My carger things they are charged. yet my blade msr and pz p-51 disagree. the life on them is very short. some are seconds. others a minute or so at WOT.

I plug them in. some charge solid for a few minutes then start to blink which means they are "almost full". my charger reconizes all them. they just have a very small winndow. VERY small. i tried charging with my hyperion charger with similar results. I keep discharging and recharging which may have helped a little. not much. Am i just screwed? these 1s batteries seem very delicate. im going to try a hyperion 130 and 160mah. maybe pz batteries just suck?
ecszone is offline Find More Posts by ecszone
Reply With Quote
Old Dec 26, 2010, 03:04 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
They probably discharged while sitting in the charger. Many (most) chargers do not completely disconnect from the battery when turned off. They will continuously suck a little bit out of the pack when unpowered. I'm guessing you over-discharged them which can permanently damage them.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Jan 01, 2011, 06:34 AM
Registered User
Joined Dec 2010
4 Posts
hi and happy new year
i have a problem with a 11.1v 3 cell battery because the older charger walkera ga-002 was charging just 2cells.
so yesterday i got a new imax b6 , it says 4.20v for the 2 cells and 1.9v for the last one .
when try charging or balancing it goes 1mn than shows a full battery message , i tried discharging but its only the 1.9v cell that goes to 0.8v the others lows to 4.12v i couldn`t get lower voltage ...

what do you advise me to do? is it possible that the battery is dead ?

li po 4000mah 11.1v + imax b6
thanks for help
dready is offline Find More Posts by dready
Reply With Quote
Old Jan 01, 2011, 03:36 PM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
21,158 Posts
The battery is probably a candidate for a 2-cell pack or the garbage. Cells under 2.5V for any length of time can be permanently damaged. The only thing you could try is charging the 1.9V cell up to 4.2V by charging that one through the balance tap by itself.

Beware! Damaged packs like this one can be unsafe. I'd treat this one especially like a fire ready to happen. If you do anything, I'd recommend doing it outside in a fire safe place and always storing it in a fire safe place.
hoppy is offline Find More Posts by hoppy
Reply With Quote
Old Jan 01, 2011, 10:01 PM
Registered User
Joined Dec 2010
4 Posts
Thanks for help Hopy , im going to buy a new one , best thing to do
dready is offline Find More Posts by dready
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion unbalanced pack... Is my battery pack DEAD? jnyoun Batteries and Chargers 1 Apr 14, 2009 09:09 PM
Discussion i think my lipo is dead..help..pls.. barok Batteries and Chargers 8 Apr 01, 2007 11:00 PM
My LCD Display is dead! help! Markz DIY Electronics 4 Mar 25, 2004 10:26 AM
My RE 12 went dead!!! help please Extra330 Radios 30 Mar 23, 2004 06:34 PM
Question Lithium-Ion Battery help/info needed. splaice Batteries and Chargers 4 Jun 06, 2003 08:50 PM